The invention concerns a clamping closure for the releasable joining of the locking strip of cases, writing cases, and the like, wherein the main body of structures of this type have a lower part comprising a spring and an upper part which, upon the pressing together of the upper and the lower part, lockingly and releasably engages said spring.
German Pat. No. 27 38 122 concerns a clamping connection wherein a base plate of a lower part is provided with four perforations arranged on a circular circumference and enclosing strips opposing each other in pairs. The lower part of the clamping closure according to German Pat. No. 27 38 122 further comprises a cap equipped with four lugs corresponding to the perforations of the base plate, with said cap being joined to the base plate by pressing the lugs into the perforations. Outside the area of the strip, the cap has a semicylindrical peripheral wall with a height less than that of the lugs, wherein the peripheral wall is perforated to the covering surface of the cap between two closely adjacent lugs. Circumferential projections of a slit annular spring set into the cap protrude through these perforations so that in the web areas, after the assembly of the lower part, protrude radially and springingly past the outer circumference of the cap. The upper part of the clamping closure comprises a clamping plate provided with a circular opening essentially corresponding to the diameter of the cap, while on the opening edge facing the lower part a spring projection is provided for the purpose of depressing the circumferential projections of the annular spring for the locking engagement of said annular spring with the base plate.
The known clamping closure is extremely convenient and reliable in practical use. Certain disadvantages have, however, arisen from the fact that the four small projections of the cap may break off under extreme stress exposures, so that the joint between the cap and the base plate is partially susceptible to release or damage in a detrimental manner.